1. Field of the Invention
The present invention relates to a cylindrical body of a paper material constituting a fiber drum and a method of fabricating the cylindrical body.
2. Prior Art
A conventional cylindrical body of a fiber drum is made of a roll of a paper material, and its opening edges at both upper and lower ends of the roll are inwardly curled together with metal rings for reinforcement, thus forming inwardly curled annular portions.
When the fiber drum is used for storage of powder or granules of medical product or fine chemical, it may be provided with an inner bag or container made of a synthetic resin material for being air-tightly filled with the powder or granules. Yet, if the inner bag or container is fouled with dust of the paper material of the cylindrical body, it may appear as suffering from leakage or contamination from the paper dust, and its quality management will hardly be qualified. Accordingly, it is a major issue to inhibit the generation of paper dust.
The present invention is developed in view of the above aspects and its object is to provide a cylindrical body of a fiber drum which can prevent the generation of paper dust while the opening edges of a roll thereof are being shaped, improve the physical strength of the opening edges, and facilitate its recycling and a method of fabricating the cylindrical body.
For achievement of the object, a cylindrical body of a fiber drum according to the present invention is featured in which at least one opening edge, or the other opening edge, of a roll made of a cylindrical paper material has an inwardly or outwardly curled portion and is protected at its outer surface with a protective material. This will increase the physical strength of the one or other opening edge. Also, if the curled end of the curled portion is injured or cracked, its outer surface is protected with the protective material, thus inhibiting paper dust generated at the injury or cracks from dispersing to the outside.
The protective material may preferably be a length of paper tape. This will require no particular separation of the protective material from the roll during the disposal process.
A method of fabricating the cylindrical body of a fiber drum according to the present invention is provided. The method comprising the steps of: winding a length of paper sheet into layers, between which layers an adhesive is applied to form a roll; providing a protective material on the opening edge at either one or the other opening end of the roll; and curling inwardly or outwardly the opening edge at either the one or the other opening end of the roll together with the protective material, before the adhesive between the paper layers is completely cured, to form a curled portion covered at the outer surface thereof with the protective material. As the curled portion is formed within a short period of time, a number of the cylindrical bodies can be fabricated at higher efficiency.